In the personal authentication in the access management or the automatic settling system, the identification of the user in using the computer or the mobile phone, and so forth, an iris image obtained by shooting the eye is utilized. In order to put exactly a position of the eye to be shot onto an optical axis of an imaging optical system, the eye image pick-up system for shooting the eye utilizes the eye position guiding device.
For instance, in the eye image pick-up system in Patent Application No. 2000-367389 filed previously by the applicant of this application, as shown in FIG. 15(a), the eye position guiding device including a lens-barrel 112 provided concentrically with the optical axis of the imaging optical system, an objective lens 113, a mirror 114 for changing an optical path of the imaging optical system, an LED 115 arranged at the back of the mirror 114 on a prolonged line of the optical axis to emit a visible light, and an imaging device 116 for picking up the image of the eye is provided.
As shown in FIG. 15(b), the mirror 114 has a reflecting surface 118 formed of a deposited film, or the like made of reflecting material, and a transparent light guiding portion 119 provided concentrically with the optical axis and not deposited. As shown in FIG. 15(c), in the case where the eye to be shot is put onto the optical axis, a light of the LED 115 passed through the light guiding portion 119 appears as a guiding visible light in the lens-barrel 112 when the user views from a front edge of the lens-barrel 112. In contrast, in the case where the eye is displaced from the optical axis, the light of the LED 115 does not appear in the lens-barrel 112. Therefore, when the user as a subject moves his or her eye to find the light of the LED 115, the user's eye is guided onto the optical axis.
However, in the above eye position guiding device, a range within which the user can look at the light of the LED 115 via the lens-barrel 112 is narrow. Therefore, it is difficult for the user to find the light of the LED and thus in some cases it takes a lot of time to put the position of the eye onto the optical path.
Also, it is hard to decide whether or not the image of the eye to be shot is focused properly, and thus it is sometimes hard to decide in which direction the position of the eye should be moved back and forth to focus. In addition, it is sometimes hard to discriminate with which eye of left and right eyes the user looks at the LED.
Also, the light guiding portion is formed by removing the deposited portion from a mirror, which is formed by depositing aluminum on a transparent substrate such as a glass plate, or the like, by means of the etching process. Therefore, the steps become complicated and thus in some cases a production cost is increased.